Generally speaking every Catholic church is unique, as architects have differing views on how to build a church. Even when a church is modeled on another church, there will always be something unique about it.
Yet, the Church encourages architects to ensure that the church they design be able to facilitate private prayer.
Silent love
The Catechism of the Catholic Church mentions this in its section on the liturgy:
A church must also be a space that invites us to the recollection and silent prayer that extend and internalize the great prayer of the Eucharist.
The Catechism expands on this concept of silent and contemplative prayer, explaining its importance to a Christian's spiritual life:
Contemplative prayer is silence, the "symbol of the world to come" or "silent love." Words in this kind of prayer are not speeches; they are like kindling that feeds the fire of love. In this silence, unbearable to the "outer" man, the Father speaks to us his incarnate Word, who suffered, died, and rose; in this silence the Spirit of adoption enables us to share in the prayer of Jesus.
Certainly churches are designed for communal gatherings of divine worship, but especially after the liturgy is concluded, the church should allow for silent and contemplative prayer.
Silent prayer is an essential part of anyone's spiritual life and churches should make sure that they provide the opportunity for it.
In some churches there is a specific chapel of the Blessed Sacrament that can allow for such prayer. In the case of many small churches, it simply means parishioners leaving the church building to socialize outside, allowing for those who wish to remain in silent prayer.
We all need to be filled by the grace of God and to listen in the silence of our heart to what God may be wanting to tell us. This is why churches need to "invite us" to "recollection and silent prayer."
